The Right Blogging Software

Hi,

I'm an elementary school teacher in B.C. Canada and I'm looking for the right blogging software to implement in my school. My whole intermediate division would like to use one blog, but we need a way to filter comments by name so we can evaluate and assess students responses to post individually.

Perhaps you know of a blogging web 2.0 tool that has a built in administrator page were all responses to posts/comments are reported. If you know of such a tool please respond.

Thanks

Christopher